This produces duplicates in the database.
Could you clarify the above please

Yes, these could potentially be consolidated. The first table was introduced earlier (Pre RBAC) in order to provide valid user choices when managing Issues. By the time the application has progressed to Chapter 8 (RBAC), there is really no situation in which a user is associated to a project and not also in one or more expllcit roles. There are several places where this Trackstar application could use a little refactoring..perhaps this is one such place.